In a Dynamic Spectrum Management (DSM) system, one or more channel metrics may be used to estimate the quality of respective channels. For example, a Received Signal Strength Indicator (RSSI) associated with a channel may be measured, for instance at the physical layer (PHY). A physical layer RSSI (PHY RSSI) measurement may be used in a channel ranking process employed by the DSM system.
A DSM engine associated with the DSM system may be configured with a primary channel and one or more non-primary channels (e.g., a primary channel and up to three non-primary channels in a channel aggregation).
Typically, PHY RSSI measurements of a channel may be made only when a packet is received, for example a data packet and/or an acknowledgment (ACK) in a data frame, or the like. The primary channel of a channel aggregation may be used to maintain authentication and/or an association between a DSM engine (e.g., implemented in an access point (AP)) and a client of the DSM system (e.g., a station (STA)). A PHY RSSI measurement may be obtained for the primary channel in accordance with a regular interval, for example, when packets are exchanged in order to maintain the association between the AP and the STA.
When non-primary channels are part of a channel aggregation, there may be scenarios where there may be no in the uplink (UL) data and/or ACKs sent from the STA to the AP such that the AP may not be able to perform PHY RSSI measurements on one or more of the non-primary channels. Without adequate channel quality measurements of the non-primary channels, a channel ranking performed by the DSM engine may result in the selection of poor quality channels, which may result in lower throughput rates.
A medium access control (MAC) level carrier aggregation system may be used to aggregate multiple physical layer chains at the MAC layer. Because these PHY chains operate on different spectral fragments (e.g., channels), the quality on each link could be different and dependent on co-channel or adjacent channel interference levels, propagation loss, transmit power, receiver noise floor, spectrum flatness, etc. corresponding to each channel.